1. Field of Invention
This invention relates to beds, mattresses and box springs and, more specifically, to a device for correcting a sagging bed.
2. Background of the Invention
When a bed becomes worn, it tends to sag in the middle greatly reducing posture support and comfort. A sagging bed results from deformation of the mattress and box spring components during normal use. The volume of the mattress deformation manifests itself as a shallow paraboloid shape. Additionally, the top of a worn mattress experiences degradation in firmness. A sagging mattress can be the source of numerous physical and psychological ailments. Initially, the purchase of a new mattress and box spring can remedy this situation, However, a new bed is expensive and will eventually succumb to sagging through normal use. Many types of prior art have attempted to correct this sagging, each with distinct disadvantages:                a) Bed boards are inserted between the box spring and mattress. However, this merely stiffens the bed and does not address the deformed sagging mattress. Nor, do bed boards address mattress top firmness degradation.        b) Inserts, composed of foam or, pads of wadding or stuffing, are inserted between the box spring and mattress such as U.S. Pat. No. 3,751,742 (1973) to Worley. All of these types of inserts have only a singular size, thickness and firmness that have cross sections with straight line contours. These straight line contours cause pressure points on the body that greatly reduce comfort. U.S. Pat. No. 1,742,108 (1929) to Taylor discloses a compensating pad that can be placed above or below a worn mattress. Additionally, two of Taylor's pads can be used back to back. However, Taylor's pads have only one size, one thickness and one degree of firmness rendering them unable to correct varying amounts of sagging. Nor, can Taylor's pads provide varying amounts of mattress top firmness correction.        c) One or more inflatable bladders are placed between mattress and box spring such as U.S. Pat. No. 4,745,645 (1987) to McWilliams and U.S. Pat. No. 6,665,898 (2003) to Gordon. This type of device is adjustable but, requires expensive air pumps, hoses, and valves or control mechanisms. Multi-bladder inflatable inserts have stepped cross-sections and straight edges that cause pressure points. The bladders themselves can cause uneven support that has the sensation of “rolling on a beach ball”. Also, these bladders can develop leaks thereby negating any support. Nor, do inflatable bladders address mattress top firmness degradation.        d) A mechanical expansion device adjustable by a crank handle is placed between mattress and box spring as discloses in U.S. Pat. No. 2,545,310 (1951) to Rosenberger. This type of device is adjustable but, it is stiff and expensive to manufacture. Additionally, this device only addresses the sag in the longitudinal direction. Nor, does Rosenberger's device address mattress top firmness degradation.        
None of the previous art employs a paraboloid shape which would produce even support and eliminate undesirable pressure points. Except the stuffed pad (Worley), no previous art can be used on top of the mattress. However, the stuffed pad is not adjustable and only has one size, one thickness and one firmness setting. None of the previous art has a customizable base size that can be trimmed for non-standard size bedding. Additionally, the degree of mattress sagging varies depending on factors such as age, use, design and size. A solution is need that is adjustable, inexpensive and easy to use for correcting the sag of a mattress and box spring and, can also modify the mattress top firmness.